固溶时效处理Ti-600合金的蠕变行为研究

Creep Behavior of Ti-600 Alloy Solutioned and Aged at α+β Region

摘要:

研究了经α+β两相区固溶+时效处理的Ti-600合金3种温度(550、600、650 ℃)、3种应力(250、300、350 MPa)下的蠕变性能，通过合金的稳态蠕变速率数值求解了合金的蠕变激活能和蠕变应力指数n，并引入临界应力σ0获得合金的真实应力指数p，最后对合金的蠕变机制进行了分析。结果表明，蠕变温度升高、蠕变应力增加时，Ti-600合金的稳态蠕变速率增大，稳态蠕变时间缩短。Ti-600合金的名义蠕变激活能为473.5 kJ/mol。600和650 ℃下，合金的临界应力σ0值分别为103.1和42.1 MPa；应力指数n分别为6.5和4.9；真实应力指数p值分别为4.23和4.22。同时构建了该合金600和650 ℃下的稳态蠕变速率本构方程。本实验条件下合金的蠕变均为位错攀移机制

Abstract:

Creep tests were carried out on Ti-600 alloy at the temperature of 550, 600 and 650 oC, and with the stresses of 250, 300 and 350 MPa. Steady state creep rate, stress exponent n, activation energy Q at different temperatures and various stresses were calculated for the alloy. Threshold stress σ0 was introduced to get the true stress exponent p. Creep deformation mechanism was also investigated. The results indicate that the steady state creep rate will increase with the rise of temperature and stress, and the creep time will be shortened at the same time. The nominal creep activation energy for the alloy is 473.5 kJ/mol. At 600 and 650 oC, the threshold stress is 103.1 and 42.1 MPa, respectively; n is 6.5 and 4.9, respectively; p is 4.23 and 4.22, respectively. Constitutive equations of steady state creep rate for the alloy were established both at 600 and at 650 oC. The main creep deformation mechanism for the alloy is dislocation climbing